Warning for Green and Black Tea Drinks!

Green Tea is a very popular drink not only in Asian countries, but throughout the world.  In western nations, black tea is probably even more popular.

Green tea itself has many potential health benefits including promoting weight loss as well as beneficial effects on glucose tolerance (potentially beneficial for people with diabetes).  Both green as well as black teas are rich in polyphenols which are antioxidants.

Despite the many potential health benefits of both green and black teas, a recent study suggests that there maybe one important adverse health-related effect related to tea consumption.

Folic Acid:

Folic acid is an important vitamin for several reasons.  Deficiencies of folic acid have been linked to the followingconditions:

  • cardiovascular disease
  • growth retardation
  • megaloblastic anemia
  • neural tube defects (in children born from mother’s who have deficiency during pregnancy)
  • depression
  • increased levels of homocysteine

A recent study published in the journal, Biopharmaceutics & Drug disposition (Alemdaroglu et al, 2008), suggests that drinking either green or black tea may actually lower the bioavailability of folic acid.

Study Results:

At the 0.4 mg folic acid dose, green and black tea reduced the mean C(max) of serum folate by 39.2% and 38.6%

Study conclusion:

The present results suggest an in vivo interaction between tea and folic acid with even low concentrations of green and black tea extracts yielding decreased bioavailabilities of folic acid.

Important Implications:

  • Pregnant women may want to eliminate or at least restrict their consumption of both green/black tea.  Lower folic acid bioavailability is a potential risk for neural tube defects.
  • For those who do consume green/black teas, you will want to ensure that you don’t take your vitamins (containing folic acid) with tea.

Reference:

  1. Alemdaroglu NC, Dietz U, Wolffram S, Spahn-Langguth H, Langguth P. Influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability. Biopharm Drug Dispos. 2008 Sep;29(6):335-48.

7 thoughts on “Warning for Green and Black Tea Drinks!

  1. It’s kind of ironic…I drink black tea at night as a way of relaxing. According to this report, that has the potential to reduce folic acid levels. This in turn could lead to depression.

    Funny.

    To me, the only positive effect of drinking tea is in your mind. If it reduces stress and helps you relax and unwind, I say it is good for you. Direct physical effects? Negligible.

  2. Kenneth and Stumulite, thank you both for your recent comments. Both green and black tea both have several potential health benefits. I am not suggesting that people should stop drinking either type of tea. However, pregnant women should be cautioned about the potential effects on folic acid. Additionally, many people who drink tea also take vitamins and supplements. For those who do, they should definitely not take a B-complex vitamin when they are drinking tea.

  3. This is very interesting. I am a big Yerba Mate tea drinker and generally drink my tea first thing in the AM and mid afternoon or evening. Vitamins always with a meal so I’m guess I probably shouldn’t worry about my folic acid levels. I have always been taught to take vitamins with meals so that the fat soluble vitamins have something to bind to. Thanks for the information, I appreciate you bringing it to the table. Certainly helps to make wiser decisions when drinking or eating anything.

    SpinDiva!!

  4. This article was very interesting. I guess there are always bad side effects to even seemingly good things. I can’t wait to see what you post next.

  5. I wasn’t aware that green tea had any adverse effects. Your blog is full of so many interesting facts!

    Lisa

  6. Hey could I quote some of the insight found in this entry if I reference you with a link back to your site?

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